Pulmonary Embolism Rule-out Criteria - Is it good enough? DR. IMRON SUBHAN MBBS, FEM (CMC), MRCEM CONSULTANT & HEAD DEPARTMENT OF EMERGENCY MEDICINE APOLLO HOSPITALS HYDERABAD INDIA GENERAL SECRETARY SOCIETY FOR EMERGENCY MEDICINE INDIA
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Massive Pulmonary Embolism Classical Signs and Symptoms Severe shortness of breath Chest pain Distress ECG changes ECHO findings Such patients easily trigger investigations/ consults/resuscitative treatment
What is difficult to identify No shock No chest pain Minimal SOB Mild discomfort Vitals normal No symptoms
Undiagnosed PE The Silent Killer 1 in 1000 patients has venous thromboembolism 400000 patients present with DVT / PE every year in USA 10000 patients die each year with DVT / PE Half of the cases are never diagnosed No data
Main Stay of Treatment Clinical suspicion Point-of-care / Bedside tests D-Dimer CT angiography Confirmation of diagnosis Thrombolysis / Anticoagulation Hospitalization
Scores used to identify / risk stratify PE Well s Score Modified Well s Score Simplified Well s Score BMJ Simplified Well s Score Geneva Score Revised Geneva Score Simplified version of Geneva Score PERC
Pulmonary Embolism Rule-out Criteria - PERC Clinical diagnostic rule designed to exclude PE. PE can be RULED OUT if all 8 criteria are met Age < 50 Pulse < 100 SaO2 >95% No hemoptysis No estrogen use No surgery or trauma in 4 weeks No previous venous thromboembolism No unilateral leg swelling 8 PERC CRITERIA
Case 30 year old man Healthy, no risk factors Exercises daily Vague lower back pain, after a workout session Redness and mild swelling of right thigh Color doppler CT angiography NO scoring systems used on this patient
Clinical Experience / Decision Making Also known as CLINICAL GESTALT Gut instinct Expert s calculated risk Very important component in assessment of a patient suspected to have PE. Since clinical experience varies, scoring systems are used to achieve a certain standard of care. Objective criteria or gestalt clinical assessment may be used to risk stratify patients. ACEP
Advantages of PERC Rapid and easy Avoids unnecessary investigations Avoids risks related to CT radiation and contrast injection Saved costs (D-dimer, CT angio, consults) Avoided inter-hospital / higher hospital transfers Returns focus on alternate diagnoses
Problems with PERC Scoring will fail where - Tachycardia is masked (beta blockers) Leg swelling cannot be detected (obese patients) Long standing hypoxemia (ILD) History is unreliable (No family with patient)
Evidence Supporting PERC PERC alone cannot safely identify very low risk patients Hugle et all, 2011 In patients with low probability of PE, use PERC to exclude diagnosis ACEP, Level B Recommendation PERC is currently being validated in various settings.
Comparison with other scores Modified Well s Score Used to assess the clinical probability of PE. To determine whether PE is likely or unlikely. Revised Geneva Score Low / Intermediate / High probability 8-point PERC Is only used a rule-out criteria
Ideal Suggestion Risk Stratify PERC Clinical Decision
Summary American College of Physicians - 2015 Categorize the risk Well s Score or Revised Geneva Score. If patient is at low risk Use the PERC. If patient meets all 8 criteria, no further testing is needed (Risks of testing are greater than the risk of embolism). If patient at intermediate risk or PERC not met D-Dimer test should be initial investigation. If D-Dimer < 500ng (upto 50yrs age) - then no imaging needed. For high risk patient Perform CT angiography directly
Take Home Points Subclinical pulmonary embolism is difficult to identify. Start tracking your patient data. PE scoring systems must be supported by the clinical decision of senior EM physician. PERC is simple and rapid way to rule out PE in low risk patients. Await results of ongoing trials validating PERC (Eg: PROPER). PERC is good enough! To rule out only. And not for all patients.
Thank you for your time Special thanks to Dr. Basar Candar & Team 3 rd Intercontinental Emergency Medicine Congress